Orstavik K H
Thromb Haemost. 1981 Dec 23;46(4):684-6.
We have previously demonstrated that neutralization of factor IX in normal plasma by heterologous antisera shortens the one stage prothrombin time determined with bovine thromboplastin. In this study, a similar effect of homologous antibodies was demonstrated. Addition of plasma from two patients with hemophilia B- and an acquired inhibitor to factor IX gave a shortening of the prothrombin time of plasma from normal persons, compared to the prothrombin time determined after addition of control plasma from a patient with hemophilia B- and no inhibitor. Addition of inhibitor plasma had a similar effect on the prothrombin time of plasma from four patients with hemophilia B+ and one patient with hemophilia BM, but had no effect on the prothrombin time of plasma from ten patients with hemophilia B-. Complexes between factor IX and the human inhibitor could be demonstrated both before and after the coagulation with bovine thromboplastin. These complexes were demonstrated as a factor IX antigen with a reduced electrophoretic mobility in crossed immunoelectrophoresis against a rabbit antiserum to factor IX. The results demonstrate that normal factor IX loses the ability to act as an inhibitor in the coagulation with bovine thromboplastin after having formed a soluble complex with a homologous antibody, although the factor IX molecules still have antigenic determinants which are free to react with the rabbit antibodies.
我们之前已经证明，用异种抗血清中和正常血浆中的因子IX会缩短用牛凝血活酶测定的一期凝血酶原时间。在本研究中，证明了同源抗体也有类似作用。与添加来自一名无抑制剂的B型血友病患者的对照血浆后测定的凝血酶原时间相比，添加来自两名B型血友病患者和一名获得性因子IX抑制剂患者的血浆会使正常人血浆的凝血酶原时间缩短。添加抑制剂血浆对四名B型血友病患者和一名BM型血友病患者的血浆凝血酶原时间有类似作用，但对十名B型血友病患者的血浆凝血酶原时间没有影响。在用牛凝血活酶凝血之前和之后，均可证明因子IX与人类抑制剂之间形成了复合物。在与兔抗因子IX抗血清进行的交叉免疫电泳中，这些复合物表现为电泳迁移率降低的因子IX抗原。结果表明，正常因子IX在与同源抗体形成可溶性复合物后，在与牛凝血活酶的凝血过程中失去了作为抑制剂的能力，尽管因子IX分子仍具有可与兔抗体自由反应的抗原决定簇。
